The objective of the proposed research is the determination of the synaptic mechanisms and functional interactions used by the vertebrate retina and visual system to process visual information. Of particular interest is the neural basis for lateral spread of adaptive effects, sites of desensitization in dark-adaptation, spread of adaptation along retinal rods, lateral spread of adaptation among photoreceptors, dark adaptation and pigment regeneration, the origins of the b-wave of erg, the light induced release and uptake of potassium in retina, differences between rod and cone adaptive mechanisms, and the functional basis of amblyopia. These objectives will be approached by recording ganglion cell discharges from optic tract fibers of the rat and the gray squirrel with metal microelectrodes, recording intraretinal potassium changes in frog and toad retina with ion electrodes, measuring intracellular responses from toad rods with glass micropipettes, recording rod membrane currents with suction electrodes, and exploring the visual capacities of cats.